Balance-spring having elasticity increasing with a rise in temperature.



UNTTED sTATEs PATENT caricia.

cieiiAnLEs EDCUARD GUILLAUME, oF svRns, FRANCE, AssIGNoR To sooU'J'n DES.rABRIQUEs DE SPIRAUX mtUNIEs, or LA CHAUX-DE-FONDS, SWITZERLAND.

$F I ANCESPRI NG HAVING ELASTICITY INCREASING WI-TH A RISE INTEMPERATURE.

Lioaeoc. No Drawing.

T0 all whowtz't may concern Be it known that I, CHARLES EDOUARDGUILLAUME, doctor of philosophy and as'- `sistant director of theInternational Office of Weights and Measures, a citizen of the SwissRepublic, and resident of Svres, Department of Seine-et-Oise, France,have invented new and useful Improvements in Balance-Springs HavingElasticity Increasing with a Rise in Temperature, of which the followingis a full, clear, and eXact speci# ication.

For l,some years escapements have been made having balance springs, theelasticity of which increases with the temperature, for the purpose ofcompensating in great measure the increase of the inertia of the balancewheel as the temperature rises. It has been shown in United StatesLetters Patent No. 669763, dated March 12th 1901 and British LettersPatent No. 11825 of 1898, that theavrequired increase of elasticityvwith temperature is exhibited by balance I thereof are known as springsmade of nickle-steel containing from 27-28 per cent. of nickel or 39-45per cent. of nickel. The first alloy has alone found application inpractice and balance springs Paul Perret springs. Accordingly vas thecompensation is more or less complete these springs are known in thetrade as compensated, halfcompensated or quarter-compensated; it is tobe remarked, however, that in practice none of these balance springsexhibits an absolute and complete compensation. In most cases there isobtained only a partial compensation by .the use of these balancesprings, the elasticity of which increases with the tem erature. It hasbeen found that these-nic el-steel balance springs containing 27-28 percent. of nickel, while giving the aforesaid results, are very soft andin consequence very easily deformed; in other terms their limit ofelasticity is very low, 'indeed so low that they have been compared withleaden springs by watcli-makers- The fact is that if they are not madewith great care they undergo small permanent deformations when they aremade part of an escapement, the balance .wheel of which oscillates withconsiderable amplitude. This is a very serious defect in the regulation,a balance spring which is too soft hav Specification of Letters Patent.

Application filed February 20, 1912. Serial No. 679,302.

Patented Aug. 4, 1914.

ing always been considered by watchmakers as of inferior quality. Thisis also the reason why these balance springs have not received a veryextended ap lication and have -not been used hitherto with success foraccurate regulation of time pieces for the purpose of chronometric`computations in observatories.

The successful employment ofl balance springs having an elasticity whichincreases with the temperature for watches of very good qualities andfor scientific instruments .of high precision-was depending of themanufacture of a balance spr-ing of a high limit of elasticity. Varioushardening agents are known in metallurgy, but in the present case notall of them are able to be employed with `success, the manufacture ofbalance springs having to overcome great difficulties for the followingreasons: 1. Thealloy employed must be able to be laminated "and to bedrawn to very small diameters.

2. It must be throughout homogeneous, in order that the balancel"springs mad'e'of it may have uniform properties.

After numerous experiences applicant succeeded in the manufacture of analloy fulfilling all th` peciied conditions. principal compfitsr'l ofthis alloy are in a known manner iron Iand nickel with convenientadditions. Among these additions always are ina known manner smallquantities of carbon and of silicon and eventually a larger quantity ofmanganese.' Further essential additions for the present invention are atleast two metals of the sixth group of the classification ofMendelejerf, as for instance, chromium and tungsten, chromium andmolybdenum, tungsten and molybdenum', chromium, molybdenum and tungsten.

The content of nickel in the alloy is hereby not maintained as hithertobetween .27 and Q8 per cent., but can vary between 27 and 31% with thequantity of the other elements. Carbon and silicon` are employed inployed in quantities of,0.2 to 4% and that in such a manner that thetotal amount of them and of the carbon and silicon or car- The ino

bon, silicon and manganese is comprised be tween 3.5 to lOper cent. ofthe whole alloy.'

to a certain extent on the impurities which lusually accompany theseveral elements constituting the alloy used even when these alloys aremade from the most pure products obtainable by metallurgy; thisdependence is such that two alloys prepared trom elements ,in the sameapparent proportions from maf` l terials technically pure but'ofdifferent orin 'fio gin have not exactly the same elastic properties.Even when using the saine materials the alloys obtained have not alwaysstrictly Jthe same composition and the same elastic properties; thisarises from the fact that during the fusion of the alloy certainelements may be more or less oxidized in the crucible and thus pass intothe slag; the i alloy has not then strictly the composition representedby the proportions of the products used for preparing it. @ne cannottherefore prescribe strict and absolute proportions and it can only besaid that when employing for making the alloys the pure* materialsobtainable in commerce within the aforesaid limits there is obtainedy ametal possessing to a more or less perfect degree the desiredproperties, namely elasticity increasing with rise ot temperature andhigh elastic limit. The proportions to be adopted in maling the alloyvfor the spring vary moreover to a certain extent with the nature ot themetals used in the construction of the balance wheel to which the springis to be applied. n

By way oi examplelthe composition oli an alloy suitable for springsaccording to this invention is given here:

l/'Vhat l claim is: l. A balance spring of which the elasticity lincreases with rise or" temperatureand which has a high elastic limit,consisting of an alloy of iron and nickel containing between 27 and 81per cent. of niclrel'and besides of small quantities of carbon and ofsilicon at least two metals of the sixth group of the Vclassification ofMendelejed, each 03E these metals being in such a proportion between 0.2and t per cent.. that the total amount oli these metals and oit thecarbon and silicon in the alloy is between 3.5 and l0 per cent. ot thewhole alloy.

2 A balance spring of which the elasticity increases with rise ottemperature and which has a high elastic limit, consisting ot an alloyof iron and nickel containing betweenv '27 and 31 per cent. ot nickeland esides oi small quantities of carbon and of silicon 'and of l to aer cent. of manganese at least two metals o the sixth group oi' theclassihcation of Mendelejei, each ot these two latter metals being insuch a proportion between 02 and 4iper cent., that the total amount of ithese metals and of the carbon, manganese and silicon in the alloy isbetween 3.5 and l0 per cent. ot the whole alloy.

3. A balance spring of which the elasticity increases with rise oftemperature and which has a high elastic limit, consisting ot an alitiloy of iron and nichel containing between 2( and 3l per cent. ot nickeland besides ot small quantities of carbon and ota silicon, chromium andanother metal of the sixth group of the classihcation ot ll/lendelejetl,each of'these two metals of said group being in such a-propoitionbetween 0.2 and i per cent., that the total amount oi3 these metals andofthe carbon and silicon in the alloy is between 3.5 and l0 per cent. ofthe whole alloy.

Si. A, balance spring of whicrhvthe elasticity increases with rise oftemperature and which has a high elastic limit, consistingof an alloy ofiron and nichel containing between 27 and 3l per cent. of nichel andbesides of small quantities of carbon and of silicon and of l to Llpercent. of manganese chromium and another metal of the sixth group ci" the1 and 3l per cent. of nichel and besides of small quantities oie carbonand of silicon chromium and tungsten, each of these two latter metalsbeine in such a nro ortion bei tween 0.2 and i per cent that the totalamount or these metals and ci the carbon and silicon in the alloy isbetween 3.5 and l0. per cent. of the whole alloy.

6. A balance spring of which the elasticity increases with rise oftemperature and which has a high elastic limit, consisting 'of an alloyot iron and nickel containing between 27 and 3l per cent. of nickel andbesides of small quantities of carbon and of silicon and of fu ver cent.of manganese chromium und tungsten, each of these two latter metalsbeing '1n such a proportion between 0.2 and per cent., that the totalamount. of these e nxt-me and of the carbon, manganese and silicon n thealloy s between 3.5,and 10 per cent. of the whole lalloy.

In witness whereof I have hereunto signed my name this 7 th day ofFebruary 1912, in the presence of two subscribing Witnesses. 10

CHARLES EDOUARD GUILLAUME.

VtnessQs CHARLES ALBERT VERILLE, BARTLEY F. YosT.

